Rufus n



(N6 Moden R. N. PRATT. PLUG COCK.

No. 583,122. Patented May 25 1897.

l UNM UNITED STATES PATENT OFFICE.

RUEUS N. PRATT, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE PRATT da CADYCOMPANY, OF SAME PLACE.

PLUG- SPECIFICATION forming part of Letters Patent No. 583,122, datedMay 25, 1897.

v Application filed December 9, 1895. Serial No. 571,473. (No model.)

To all whom, t may concern:

Be it known that I, RUFUS N. PRATT, a citizen of the United States,residing at Hartford, in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inPlug-Cocks, of which the following is a speciiication.

The invention relates to the class of rotary plug-cocks. It is necessarywhen such cocks are employed under high pressures that the plugs shouldbe forced very tightly into the plug-chambers to prevent leakage, andthis causes such friction between the plugs and the bodies and holding-down plates that muchv power is required to rotate the plugs foropening and closing. This is particularly so with cocks of large size inwhich the plugs are `ground into the chambers; and theobject of thepresent invention is to provide a very simple and inexpensivearrangement ofthe parts of such cocks which will insure the easyrotation of the plugs, although theymay be set tightly into the bodies,allowing the plugs to be rotated easily either close at hand or at adistance by a handle or by rods and gears.

Referring to the accompanying drawings, Figure 1 is an end elevation ofa plugcock embodying the invention. Fig. 2 is a plan of the same, andFig. 3 is a central vertical longitudinal section of the cock.

In the views, l indicates the body of the cock, which may be cast toshape, of iron, brass,'or other suitable metal. This body has a circularplug-chamber tapering from one end to the other and either the commonflanged or screw-threaded ends that are shown for attachment to thepipes with which the cock is to be used. Fitting in the chamber in thisbody is a tapering rotary plug 2, having the usual duid-port 3. The bodyof the cock around the walls of the plug-chamber may be grooved andprovided with a packing material, or the plug may be ground to its seat,as shown in Fig. 3. The shank of the plug is smaller in diameter thanthe body of the plug, so as toform a shoulder 5 outside of the bodyabove the cover, and the outer end of the shank is shaped to receive awrench,

rod, or handle, by means of which it may be rotated.

The plug-chamber is shown as open from vthe top of the body only, andthis opening at the top, through which the plug is inserted, is closedby a cover G, which is held tightly in place by nuts 7, that screw uponthe studs 8. The cover has an opening for the plug, and a packing-ring 9is placed in the recess in the top of J[he chamber to pack the jointbetween the cover and the plug` and body. The compression of thispacking and the tightness of the joints may be regulated by adjustingthe nuts that hold the cover.

The plug is held down in the chamber by the adjustable holding-downplate lO. This holding-down plate is provided with a little projectionor a shoulder 1l around the opening for the plug, in which is formed agroove that is ad-apted to iit upon balls that are placed in a groove inthe shoulder 5 on the plug. The plate is held in place by nuts 12, thatare adjustable upon the studs 8. When these nuts are screwed down hard,the plate, through the medium of the balls, forces the plug into theplug-chamber and causes it to make close contact with the walls of thechamber or with the packing therein, but by Virture of the balls even ifthis plate is held down firmly by screwing the nuts hard, so the plug isforced inward with great pressure to insure a very tight joint, the plugcan be rotated easily, so that it may be turned to open and close eitherclose at hand or at a distance through long rods or shafting andgearing, as is sometimes necessary.

If the plate is not drawn down evenly by the nuts-that is, if one sideof the plate is drawn down lower than the other or if the parts expandunevenly when heated, so that one side of the plate holds tighter thanthe other-the plug does not bind in the plugchamber, for with thiscondition the plate only bears on different surfaces of the balls, andthis does not tend to throw or force the plug over to one side, as woulda plate bearing directly on a smooth hard shoulder with greater force onone side than the other. Thus the balls compensate for any unevenness ofthis nature in the holding-down plate and insure an easy rotation of theplug at all times. This is particularly advantageous with large cockswhich are subjected to varying temperatures and which are liable to eX-IOO pand considerably and bind when heated by high-pressure steam, forthe joints must be made very close and tight, and when made thus will,under the expansion of the plug, ordinarily cause such friction as torequire the application of much power to rotate the plug for openiugandclosing. If the holdingdown plates are adjusted loosely to allow an easyrotation of the plug when expanded, the cock willleak, and if there isthe slightest alnount of leaking under high pressures the metal soonbecomes so cut away that the cock is worthless. The balls can beinserted or removed from place between the shoulder on the plug outsideof and above the cover after the cover has been secured in place withoutinterfering with the packing of any joint, and the balls when located inthis position are some distance away from the fluid-way and theyare tosome extent open tothe atmosphere, as they are not as highly heated asthey would be nearer to the iiuid-way or if they were inclosed.Therefore they remain hard and in good condition for service. The ballsare located where they can be removed or new balls substituted forbroken or damaged ones without removing the cover or tipping the cockupside down. The arrangement of the parts is simple, so they are notlikely to get out of repair, and they do not require any special skillto obtain the proper adjustment, and,furthermore,the holdin g-down plateheld in this manner has more or less give, so that should the plug whenexpanding be slightly forced out of the plug-chamber the balls will notbe crushed, as they would be between the perfectly rigid plate and theexpanding plug.

I claim as my invention- A rotary plug-cock having a body with aplug-chamber, a rotary plug located in such chamber and provided with agrooved shoulder outside the body and above the cover, a cover for theplug-chamber removably secured to the body by threaded studs and nuts, apacking between the body, plug and cover that is held compressed by thecover for making tight the joints, a holding-down plate independentlyadjustable with relation to the cover, said plate being held on oppositesides of the plug by nuts that are threaded on the same studs that holdthe cover whereby the plate may be adjusted up and down on either sideindependently of the other and of the cover and said plate having agrooved shoulder outside of the body and above the cover opposite thegrooved shoulder of the plug, and antifriction-balls located partiallyin the groove in the shoulder of the adjustable holding-down plate whichthey support and partial] yin the groove of the shoulder of the plug bywhich they are supported above a-nd outside of the cover in position tobe removed without disturbing the cover or any packing and partiallyexposed to the atmosphere, substantially as specified.

RUFUS N. PRAT' \Vit1icsses:

FRANCES G. PRATT, HARRY R. XVILLIAMS.

